function D=diff_cod(A);
% Differential coding for LLLLL level
[M,N]=size(A);                     
 D=A;
 D(1,1:N)=[A(1,1) A(1,2:N)-A(1,1:N-1)];
for I=2:M,
  D(I,1:N)=A(I,1:N)-A(I-1,1:N);
end;  


